import { mkdir } from 'node:fs/promises'
import { basename, isAbsolute, join, resolve } from 'node:path'
import { createConfig } from './config/defaults.js'
import { runScenarios } from './harness/runner.js'
import {
  collectBootstrapObservability,
  collectProcessObservability,
} from './observability/adapters.js'
import {
  buildBenchmarkReport,
  buildComparisonText,
} from './reporting/report.js'
import { createCorrectnessAndToolScenarios } from './scenarios/correctnessTools.js'
import { createHeadlessScenarios } from './scenarios/headless.js'
import { createRestorationScenario } from './scenarios/restoration.js'
import { createStartupAndCommandScenarios } from './scenarios/startupCommand.js'
import type { BenchmarkMode, BenchmarkReport, BenchmarkRunKind } from './types.js'
import { readJsonFile, writeJsonFile, writeTextFile } from './utils/files.js'

function parseArg(name: string): string | undefined {
  const hit = process.argv.find(value => value.startsWith(`${name}=`))
  if (!hit) return undefined
  return hit.slice(name.length + 1)
}

function resolveMode(): BenchmarkMode {
  const raw = parseArg('--mode')
  if (raw === 'online' || raw === 'offline' || raw === 'hybrid') return raw
  return 'hybrid'
}

function resolveRunKind(): BenchmarkRunKind {
  const raw = parseArg('--run')
  if (raw === 'smoke' || raw === 'full') return raw
  return 'smoke'
}

function resolveOutputDir(rootDir: string): string {
  const input = parseArg('--out')
  if (!input) return join(rootDir, 'benchmark', 'results')
  return isAbsolute(input) ? input : resolve(rootDir, input)
}

async function runBench(): Promise<void> {
  const rootDir = process.cwd()
  const nowIso = new Date().toISOString()
  const mode = resolveMode()
  const runKind = resolveRunKind()
  const config = createConfig(mode, runKind)
  const outputDir = resolveOutputDir(rootDir)
  await mkdir(outputDir, { recursive: true })
  const context = {
    rootDir,
    mode,
    runKind,
    nowIso,
    outputDir,
  }
  const scenarios = [
    ...createStartupAndCommandScenarios(config),
    ...createHeadlessScenarios(config),
    ...createCorrectnessAndToolScenarios(config),
    createRestorationScenario(config),
  ]
  const summaries = await runScenarios({
    scenarios,
    context,
    config,
  })
  const report = buildBenchmarkReport({
    rootDir,
    generatedAt: nowIso,
    config,
    scenarios: summaries,
    observability: {
      bootstrapState: collectBootstrapObservability(),
      process: collectProcessObservability(),
    },
  })
  const reportPath = join(
    outputDir,
    `benchmark-${runKind}-${nowIso.replace(/[:.]/gu, '-')}.json`,
  )
  await writeJsonFile(reportPath, report)
  const latestPath = join(outputDir, 'latest.json')
  await writeJsonFile(latestPath, report)
  await writeTextFile(
    join(outputDir, 'latest-summary.md'),
    renderSummaryMarkdown(report, basename(reportPath)),
  )
  process.stdout.write(`Benchmark report written: ${reportPath}\n`)
  process.stdout.write(
    `Quality gate: ${report.qualityGate.passed ? 'PASS' : 'FAIL'}\n`,
  )
  if (!report.qualityGate.passed) {
    for (const reason of report.qualityGate.reasons) {
      process.stdout.write(`- ${reason}\n`)
    }
    process.exitCode = 1
  }
}

function renderSummaryMarkdown(
  report: BenchmarkReport,
  fileName: string,
): string {
  const lines: string[] = []
  lines.push('# Benchmark Summary')
  lines.push('')
  lines.push(`- Report: ${fileName}`)
  lines.push(`- Mode: ${report.mode}`)
  lines.push(`- Run: ${report.runKind}`)
  lines.push(
    `- Overall score: ${report.aggregate.score.total.toFixed(2)} (latency ${report.aggregate.score.latency.toFixed(2)}, stability ${report.aggregate.score.stability.toFixed(2)}, quality ${report.aggregate.score.quality.toFixed(2)}, cost ${report.aggregate.score.cost.toFixed(2)})`,
  )
  lines.push(`- Success rate: ${report.aggregate.successRate.toFixed(2)}%`)
  lines.push('')
  lines.push('## Scenario Results')
  for (const scenario of report.scenarios) {
    const p95 = scenario.durationMs?.p95 ?? 0
    lines.push(
      `- ${scenario.id} ${scenario.name}: success ${scenario.successRate.toFixed(2)}%, p95 ${p95.toFixed(2)}ms`,
    )
  }
  lines.push('')
  lines.push(
    `- Quality gate: ${report.qualityGate.passed ? 'PASS' : 'FAIL'} (${report.qualityGate.reasons.length} issue(s))`,
  )
  if (!report.qualityGate.passed) {
    for (const reason of report.qualityGate.reasons) {
      lines.push(`  - ${reason}`)
    }
  }
  lines.push('')
  return `${lines.join('\n')}\n`
}

async function runCompare(): Promise<void> {
  const rootDir = process.cwd()
  const outputDir = resolveOutputDir(rootDir)
  const baselinePath = parseArg('--baseline')
  const currentPath = parseArg('--current')
  if (!baselinePath || !currentPath) {
    throw new Error('--baseline and --current are required for compare mode')
  }
  const baseline = await readJsonFile<BenchmarkReport>(
    isAbsolute(baselinePath) ? baselinePath : resolve(rootDir, baselinePath),
  )
  const current = await readJsonFile<BenchmarkReport>(
    isAbsolute(currentPath) ? currentPath : resolve(rootDir, currentPath),
  )
  const text = buildComparisonText(baseline, current)
  const outPath = join(outputDir, 'comparison.md')
  await writeTextFile(outPath, text)
  process.stdout.write(`Comparison written: ${outPath}\n`)
}

const command = parseArg('--command') ?? 'run'
if (command === 'compare') {
  await runCompare()
} else {
  await runBench()
}